/**
 * @license Copyright 2018 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
 */
'use strict';

const Gatherer = require('../gatherer.js');

/**
 * Get and return `name`, `publicId`, `systemId` from
 * `document.doctype`
 * @return {{name: string, publicId: string, systemId: string} | null}
 */
function getDoctype() {
  // An example of this is warnerbros.com/archive/spacejam/movie/jam.htm
  if (!document.doctype) { // eslint-disable-line no-undef
    return null;
  }

  const {name, publicId, systemId} = document.doctype; // eslint-disable-line no-undef
  return {name, publicId, systemId};
}

class Doctype extends Gatherer {
  /**
   * @param {LH.Gatherer.PassContext} passContext
   * @return {Promise<LH.Artifacts['Doctype']>}
   */
  afterPass(passContext) {
    const driver = passContext.driver;
    return driver.evaluateAsync(`(${getDoctype.toString()}())`);
  }
}

module.exports = Doctype;
